The amount of data required to be handled by communications networks continues to rise. Next generation backbone networks will have to cope with data traffic arriving from more and faster interfaces, and will need to provide a data throughput in the range of tens or hundreds of Terabits per second (Tb/s). High-end routers in backbone networks are typically all-electronic, with all routing functions realized in the electronic domain. However, these all-electronic routers are approaching their fundamental limitations, mainly in terms of power density. Multi-rack systems have been designed to reduce this problem but this solution further increases the overall power required by the router and the router footprint, and poses problems related to inter-rack wiring and communications. All-optical packet switching networks, i.e. networks where optical packets are optically forwarded end-to-end, have been proposed but do not to satisfy the huge bandwidth and cost-effectiveness requirements of next generation backbone networks. Hybrid optical/electrical routers have been proposed, such as the hybrid electronic/optical switch system described in U.S. Pat. No. 6,647,208, in which some optical data is routed optically and other optical data is optical to electronic (O/E) converted and routed electronically, to reduce the amount of data being routed electronically, however such hybrid switches require very complicated control systems.